Overview
By default Rainbow Six Vegas does not run in a window regardless of what you might try to do. This guide provides a solution.
Introduction
Despite running on the Unreal 3 engine, Rainbow Six Vegas does not allow for windowed mode by default.
This method involves using a dummy Direct 3D 9 .dll. There are a few problems however, the biggest being that the intro movies will bug out but the rest of the game remains playable
Download
Link to download: [link]
Note the link might break. If it does, post a comment and I’ll reupload it.
Installation
Go to your Rainbow Six Vegas directory. This is commonly in
C:programfiles (x86)steamsteamappscommonRainbow Six Vegas
Now unzip the contents of the d3d9.zip into the “Binaries” folder
And voila. It should run in windowed mode.
Bugs and troubleshooting
Note that there is one critical bug that might alarm you. During the intro movies the Ubisoft logo will freeze and clicking anywhere will cause Windows to tell you the program has stopped responding.
However if you avoid clicking or just wait until the intro logos naturally stop playing the game progresses to the main menu automatically.
As well. If you change your resolution the game will return to full screen. To fix this just restart the game and it should launch in your preferred resolution in windowed mode.
The game will also be borderless so prepare for this. However it will also run in borderless fullscreen as a result.
The game will also have the titles appear in 4:3 while the rest of the game appears in 16:9. Although I don’t know if this is a bug in the .dll or if it existed in the original version.
If you have further problems. Go into the binaries folder and select d3d9.dll and right click it and make sure to select “Unblock this program” in the settings.